Earthworms are known to play integral roles in soils, and are often referred to as vital soil and ecosystem engineers. They have the ability to influence a wide range of chemical, physical, and biological ... [more ▼]

Earthworms are known to play integral roles in soils, and are often referred to as vital soil and ecosystem engineers. They have the ability to influence a wide range of chemical, physical, and biological properties of soil environment. In the present study, earthworm and soil samples were collected from wheat cultivated fields in Gembloux, Belgium under four agricultural practices: (1) conventional tillage with crop residues incorporated into the soil (CT/IN); (2) conventional tillage with crop residues exported from the field (CT/OUT); (3) reduced tillage with crop residues incorporated into the soil (RT/IN); and (4) reduced tillage with crop residues exported from the field (RT/OUT). The different agricultural practices were applied on luvisol soil for four consecutive years prior to the initiation of the current study. The purpose of this study was to research the influence of agricultural practices on earthworms with considering species and their interactions with soil properties. Results indicated that agricultural practices affected soil properties and earthworm communities. For each depth, measures of soil physico-chemical properties showed significant differences among treatments. The penetration resistance (PR) measured to a depth of 50 cm increased with increasing soil depth in all treatments. PR was significantly higher in RT compared with CT. Soil moisture was measured before PR determination. Soil samples showed higher P and K concentrations in 0 – 10 cm depth compared with other depths. The main reason for the large K and P accumulation near the soil surface is the incorporation of crop residues. Significant differences were not detected between residue incorporation depth treatments, where results showed mean earthworm abundance was respectively 182 and 180 individuals m-2 in CT and RT. Mean earthworm biomass was similarly not significantly different between CT and RT, where results were respectively 48.5 and 57.3 g.m-2. However, a significant difference was observed between IN and OUT treatments, suggesting the exportation of crop residues will limit earthworm abundance and biomass, and will mask the effect of tillage. The endogeic species Apporectodea caliginosa strongly dominated the earthworm community (64%), whereas epigeic and anecic species remained < 3% and 5% of all earthworms. Findings indicate that endogeic and epi-anecic groups appears to be highly affected by tillage practice and the exportation of crop residues. Consequently, it seems that the effect of residue exportation was stronger than tillage effect. In compacted soils, L. terrestris, L. castaneus and A. caliginosa species showed an increased abundance. The obtained results were attributable to earthworm activity and crop residues, suggesting earthworms contributed to nutrient dynamics and soil structure, particularly at increased soil depths. Overall, the results emphasise the influence of crop residues exportation on earthworm community and also, the important influence of earthworm activity on soil physico-chemical properties change, processes which are closely linked. [less ▲]

Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is one of the most important pests of tomato, reducing crop yield in greenhouses and fields, in several countries around the world. Because synthetic ... [more ▼]

Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is one of the most important pests of tomato, reducing crop yield in greenhouses and fields, in several countries around the world. Because synthetic insecticides lead to resistance and have adverse effects on natural enemies and producers’ health, there is a need for alternatives. In this study, we assess the oviposition deterring effect of O. basilicum using dual-choice behavioral assays performed in flight tunnels. Two modalities were tested, i.e. (1) a tomato plant associated either with an O. basilicum plant versus a tomato plant associated with a plastic pot only filled with potting soil, and (2) a tomato plant with basil essential oil (EO) formulated in paraffin oil (PO) versus a tomato plant with PO only. A 1 ml cylindrical polyethylene plug loaded with 100 µl of solution (formulated EO or PO) was placed on each plant as a diffuser. Forty-eight hours after the release of unsexed adult individuals randomly sampled from the rearing in the central area of the tunnel, we found that plants and EOs reduced T. absoluta oviposition behavior on a nearby located tomato plant. GC-MS analyses showed that the major constituents include estragol (73.8%), linalool (8.6%), β-elemene (2.9%) in O. basilicum essential oils and E-α-bergamotene (38.9%), methyl eugenol (26.1 %), E-β-ocimene (17.7 % ) in O. basilicum VOCs collected with solid-phase micro-extraction method. These results suggest a valuable potential of O. basilicum and associated essential oils as component of an integrated management strategy against the tomato leafminer. [less ▲]

Insects, particularly those belonging to the family Acrididae (grasshoppers), are commonly consumed as human food in many parts of the world. Grasshoppers of the species Chorthippus parallelus are ... [more ▼]

Insects, particularly those belonging to the family Acrididae (grasshoppers), are commonly consumed as human food in many parts of the world. Grasshoppers of the species Chorthippus parallelus are abundantly found throughout Europe. However, these insects were not consumed by Europeans till now, but could possibly be used as human food, which is why we investigated their chemical composition. We found that they contain high level of proteins (69%), with an excellent amino acid profile and protein digestibility (97%). Furthermore, specimens of C. parallelus have an interesting fatty acids profile and minerals composition. Preliminary toxicity assessment indicates that these insects do not exhibit toxicity towards neutrophil cells (white blood cells). These data suggest that C. parallelus could be considered for human consumption. Rearing trials done during the study show that commercial rearing could be developed to produce sufficient biomass for sustaining human consumption. [less ▲]

Background: Cucumber mosaic virus (CMV) is one of the most important viruses infecting vegetables in the fields throughout the world. Transmission efficiency of CMV could depend on the variability of ... [more ▼]

Background: Cucumber mosaic virus (CMV) is one of the most important viruses infecting vegetables in the fields throughout the world. Transmission efficiency of CMV could depend on the variability of virus strain but also aphid vector species and/or clones. Materials and Methods: By sequence analysis, the coat protein gene of CMV strains from different regions revealed that the CMV isolates used for this study belong to the same group. Both CMV strains and Myzus persicae (Sulzer) aphid clones were investigated for their role in viral dispersion by reciprocal tests on Nicotiana tabacum (L.) using the same clone of Myzus persicae towards different CMV strains or using one CMV strain on different Myzus persicae clones. Results: Virus transmission efficiency was found to be significantly influenced by selected CMV strains (from 5-30% of transmission rate for identical aphid clone) and also by the selected aphid clones (variation from 15-70% of transmission rate for identical virus strain). Conclusion: The CMV transmission efficiency depends on the variability of virus strain but also aphid vector clones. Combining the variability of CMV transmission rates for both aphid and virus sides, the prediction and modeling of virus spreading seems to be difficult to organize and are closely dependent on the variability of each protagonist-aphid and virus. [less ▲]

This presentation aimed at giving methodological keys in order to write a systematic review of the literature. It was based on the Lopes et al. 2016 - Wheat based intercropping systems for biological pest ... [more ▼]

This presentation aimed at giving methodological keys in order to write a systematic review of the literature. It was based on the Lopes et al. 2016 - Wheat based intercropping systems for biological pest control, In: Pest Management Science [less ▲]

Understanding how climate change will affect species interactions is a challenge for all branches of ecology. We have only limited understanding of how increasing temperature and atmospheric CO2 and O3 ... [more ▼]

Understanding how climate change will affect species interactions is a challenge for all branches of ecology. We have only limited understanding of how increasing temperature and atmospheric CO2 and O3 levels will affect pheromone-mediated communication among insects. Based on the existing literature, we suggest that the entire process of pheromonal communication, from production to behavioural response, is likely to be impacted by increases in temperature and modifications to atmospheric CO2 and O3 levels. We argue that insect species relying on long-range chemical signals will be most impacted, because these signals will likely suffer from longer exposure to oxidative gases during dispersal. We provide future directions for research programmes investigating the consequences of climate change on insect pheromonal communication. [less ▲]

The tomato leafminer, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), is a widespread devastating pest reported to develop on economically important solanaceous crops. The characterization of its host ... [more ▼]

The tomato leafminer, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), is a widespread devastating pest reported to develop on economically important solanaceous crops. The characterization of its host range could help to understand and prevent the dispersion behavior of the insect in the environment. In this study, the ability of T. absoluta to develop on 12 cultivated or non-cultivated plants including Solanaceae, Chenopodiaceae, Convolvulaceae, Fabaceae and Malvaceae species under laboratory conditions was assessed. For each plant species, we monitored the development times of immature stages, survival, sex ratios and adult fecundity rates. All the 6 tested non-solanaceous plants, including Chenopodium, Convolvulus and Malva species, were not able to sustain (i.e. allow growth and development) T. absoluta larvae. Among Solanaceae, Solanum species were the most suitable host plants for the pest, but others could be opportunistically colonized with fewer incidences. T. absoluta appears to be strongly related to solanaceous plants which would predominantly support self-sustaining field populations. Preventing crop infestation by removing potential host plants in the immediate field vicinity and culture rotations with non-solanaceous crops is of primary importance. [less ▲]

Using infochemicals to develop a push–pull strategy in pest control is a potential way to promote sustainable crop production. Infochemicals from plant essential oils were mixed with paraffin oil for slow ... [more ▼]

Using infochemicals to develop a push–pull strategy in pest control is a potential way to promote sustainable crop production. Infochemicals from plant essential oils were mixed with paraffin oil for slow release in field experiments on wheat to control the population density of cereal aphids and to enhance their natural enemies. (Z)-3-Hexenol (Z3H) attracted Metopolophum dirhodum and Sitobion avenae, the predominant species on wheat in Belgium, and may be a useful infochemical for aphid control by attracting aphids away from field plots. Release of (E)-β-farnesene (EBF) or a garlic extract (GE) led to a significant decrease in the abundance of wheat aphids. The main natural enemies of cereal aphids found were lacewings (47.8%), hoverflies (39.4%), and ladybirds (12.8%). Ladybird abundance varied little before the end of the wheat-growing season. Our results suggest that these chemicals can form the basis of a “push–pull” strategy for aphid biological control, with GE and EBF acting as a pestand beneficial-pulling stimulus and Z3H for aphid pulling. [less ▲]

Currently, integrated pest management that aims to reduce the use of synthetic insecticides by considering all appropriate alternative methods, is promoted. In that context, insect pathogenic fungi could ... [more ▼]

Currently, integrated pest management that aims to reduce the use of synthetic insecticides by considering all appropriate alternative methods, is promoted. In that context, insect pathogenic fungi could be developed as biopesticides in two ways: spores but also metabolites that are recognized as virulence factors. Targeting adequate fermentation method is an important requirement to obtain fungal products (i.e. spores, enzymes and metabolites) of biotechnological interest. The 'Microbial Processes and Interactions' laboratory has developed an innovative fermentation technology (referred to as ‘biofilm fermentation’) involving the growth of fungal biomass on inert supports that are immersed in a liquid nutrient medium. Confining fungal biomass on immersed inert structures provides a hybrid production system aiming to keep a solid-state physiology for sporulation and secretion of metabolites while controlling fermentation parameters. This research project proposes to transfer this technology to culture insect pathogenic fungi, such as Metarhizium anisopliae, for the production of spores and insecticidal metabolites. Development stages include the qualitative and quantitative characterization of its impact on insecticidal products as well as scale-up to industrial level. [less ▲]

Halyomorpha halys St˚al (Hemiptera, Pentatomidae) is an invasive stink bug coming from Eastern Asia. Besides causing important yields losses in orchards, crop and vegetable fields, it overwinters inside houses as agglomerates of dozens. In Europe, this Brown Marmorated Stink Bug (BMSB) was accidentally introduced in Switzerland in 2007 and has been later observed in surrounding countries (France, Italy, Germany). Based on the current US situation, we can reasonably fear that BMSB will have colonized most of Europe countries in less than a decade. If we already discern a few fungus strains that are efficient against BMSB, very little is known about their actual impact on the insect itself. So we investigated the in- fluence of a fungal infection on insect development parameters and behaviour. Olfactometry was settled to investigate the dispersion and aggregation trends, while electropenetography was used to assess the feeding behaviour. Our results will be discussed to present changes according to healthy/fungus-infected status, in relation to potential biological control for that pest. [less ▲]

Chemical signals are involved in the courtship behavior of many invertebrate and vertebrate species. Lady beetles are no exception to this rule; a significant number of published reports highlight the ... [more ▼]

Chemical signals are involved in the courtship behavior of many invertebrate and vertebrate species. Lady beetles are no exception to this rule; a significant number of published reports highlight the role of cuticular chemicals involved in the reproduction of lady beetles, including gender recognition. Recent data have also demonstrated the presence of a volatile female sex pheromone that facilitates male attraction in some species. Here, we present a synthetic overview of the current knowledge about the sexual behavior of lady beetles and associated chemicals for which the function and identification have been provided. Because lady beetles are often reared as biological control agents, the chemical cues involved in their sexual behavior could be used as components in integrated management approaches against soft-bodied hemipterans. In conclusion, this review provides new perspectives and potential developments for sustainable insect management mainly based on the semiochemicals involved in the sexual behavior of lady beetles. A better understanding of these chemical signals would help maximize their presence in areas where their predatory behavior is requested, as a result of the application of formulations inducing behavioral manipulation. [less ▲]

To address human and environmental health issues related to the use of synthetic pesticides, it is important to explore other ecological pest management approaches. Within this context, a study was ... [more ▼]

To address human and environmental health issues related to the use of synthetic pesticides, it is important to explore other ecological pest management approaches. Within this context, a study was conducted to evaluate the toxic and repellent effect of Ocimum gratissimum L. (Lamiaceae) on Myzus persicae S. (Aphididae). The toxicity of O. gratissimum essential oil (EO) was evaluated on M. persicae comparing 3 concentrations (0.001%; 0.01% and 0.1%) to a control (15% sucrose). Mortality rate and fecundity were assessed for each concentration. The observations were made daily, for 4 days, on 12 replicates per treatment. To test the repellent effect of O. gratissimum plants, 2 treatments were compared: a group of 8 Amaranthus cruentus L. (Amaranthaceae) plants with 1 plant of O. gratissimum in the middle and a group of 9 A. cruentus plants (control). The distribution of aphids was analyzed 12 days after the middle plant infestation (20 aphids per plant) for each treatment (6 replicates per treatment). O. gratissimum EO was found toxic from a concentration of 0.01%, with a mortality rate of 34% versus 12% for the control ; The fecundity felt from 30 larvae after 4 days (control) to 15 larvae for the 3 doses of the EO. The analysis with the generalized linear mixed model with Poisson error distribution followed by Turkey test (5 %) showed that EO is significantly more toxic than the control, both for mortality and fecundity (p <0.001). In association test, the population of M. persicae (15 aphids per plant) was significantly (p<0,001) lower when A. cruentus plants was associated with O. gratissimum plant than with the control (22 aphids per plant). Furthermore, the population increases gradually as one moves away from the infestation point in association test whereas it decreases in the control. With regards to these results, it appears that O. gratissimum has biocide effects on M. persicae. This plant may be used in an integrated pest management strategy in the production of vegetable to reduce the use of synthetic pesticides and avoid chemicals residues. [less ▲]